How to build a dedicated home theatre

[Prof]

Firstly to clarify, "a dedicated home theatre" means that the room you will be using will only be used for watching movies and perhaps some TV..

A home theatre can range in price from approximately $5000 - $500,000 and more !! Some American home theatres cost over 1 million dollars !!

This tutorial will describe how to build the lower end of the range..

Firstly you will need to find a suitable room..The bigger the better, but it must have four walls and a door..Open rooms connecting other rooms will not be suitable..

The other aspect of a suitable room is whether you need the theatre room acoustically removed from the rest of the house..

This requires an additional construction to the room to isolate it from the other rooms..

I will include briefly what needs to be done, but for the most part I will proceed on the basis that this will not be needed..

There are a variety of building materials that are used to construct rooms in a house..Timber or steel framing with plasterboard walls, or brick or concrete block walls..

Each of them have their own acoustic values..

The stages of the building process...

1. Selecting the room..

2. Acoustically isolating the room..

3. Selecting the wall and ceiling paint or fabric coverings..

4. Choosing the type of floor coverings..

5. Setting up the front of room for screen and speakers..

6. D.I.Y the screen or purchasing a commercially made screen..

7. Adding acoustic panels on the side walls..

8. Adding acoustic panels in the front corners..

9. Adding acoustic panels to the rear of the room..

10. Selecting the front speakers..

11. Selecting the surround speakers..

12. Selecting the subwoofer..

13. Choosing the lighting..

14..Selecting Amplifier/ receiver..and ancillary equipment

15. Selecting Blu-ray player..

16. Programming the whole system..

So as you can see there is a lot to building a dedicated home theatre..But the end result is a very satisfying movie experience.. 

More to follow..

[Prof]

Thanks Mitchell...I'm about half way through the posts now..

[Prof]

THE WIRING RUN..

In most situations you will need to run your wiring from the front screen area, to the back of the room if your equipment is there.. or to an adjacent room..

Either way you don't want see the wiring draped over the floor or even under the carpet..It maybe difficult to even lift the carpet and having bulky wiring underneath looks messy..

So how do you hide all the wiring ? If you have soffit or ceiling trays you could run the wiring overhead but you still have to bring all those wires down the wall to connect up to your equipment..

This is what I did as many other home theatre installations have done..

These are the photos of my carpeted floor near the skirting boards..

Left hand side skirting board..

Right hand side skirting board..

As you can see there are no cables on the floor..except that power board and cable..

If you look closely at the two skirting boards, you'll notice that the right side board looks a little bigger than the left..

Attached to the the right board is a white plastic extrusion..This extrusion is screwed to the skirting board and it has a cover which just clips on..

Inside the extrusion are three channels which you use to run the cables through..

The cables are separated into ..audio, video, and power..Separating the audio from the power cables is most important and this extrusion does that well..

THE CABLES..

There will be three 14ga. twin flex cables for the three front speakers..and an RG6 coax cable from the subwoofer to the Receiver..

You may also have a transmitter sensor cable running from near the screen to the equipment and this can also be placed in the extrusion....

[Prof]

THE EQUIPMENT CABINET..

This can be just a simple construction with shelves inside an open back box structure..

On the base of this cabinet you need to put four casters, so the cabinet can be turned around..

There will be times when you need to access the back of the equipment, so it needs to be mobile..

There is just one stipulation with this cabinet..DON'T PUT THE AMPLIFIER / RECEIVER INSIDE THE CABINET.!!.They need to be placed on top  so they have free air to expel any heat..

[MitchellMc]

Thanks for the new instalment, @Prof.

Likely a silly question, but are there any additional requirements for isolating the audio from the power cables? It sounds like it is enough to have them slightly separated but still within the same ducting. No interference at all? Is there a minimum distance apart we should be aiming for?

Mitchell

[Prof]

Hi Mitchell,

Basically there is no set distance to have audio and power separated..The main thing is that they don't touch each other..

Should there be a situation where the audio cable needs to cross over the power cable..then they need to cross over at 90 degrees to each other..

[Prof]

THE FRONT SPEAKERS..

Choosing the front three speakers can be a major headache with the myriad of brands, types and models..to choose from !!

There is one simple rule when it comes to speakers..PAY AS MUCH AS YOU CAN..AND THEN SOME.!!

The speakers are the most important part of any home theatre system..so buy the best you can afford..

The first thing to consider when choosing speakers is.."What is the size of the room"?..

If it's a very large room then you wouldn't want to use bookshelf speakers to provide the sound..

On the other hand if the room is fairly small..it wouldn't be a good idea to put in massive horn speakers !!

When doing listening tests to different types of speakers..don't select any speakers that have a bright sound..

Whilst they may sound good to the ears initially..they will become very tiring when listening for long sessions..

Another consideration to keep in mind when making selections is to choose speakers that have a good projection of sound..particularly if the speakers are going to be behind an acoustic screen...

Using my own situation as a guide..

I have an acoustic screen in a small room..The screen is almost wall to wall..

The type of speakers I use for the three fronts are Folded Horns..The drivers in the speakers are a German brand and the cabinets I built to a folded horn plan..

These speakers are quite powerful and project sound very well..They also have a mellow sound which is never tiring..even after 3 hrs of movies..

This type of speaker would be good for up to medium size rooms..

At the other end of the spectrum..Commercial Cinemas use massive open face horn speakers..usually standing about 1.8M tall and taller..

This size of speaker is what is needed in such a large room.,.

The horns provide the mid range and upper frequencies..The bass is usually a simple bass reflex system using four 12" or 15" speakers in each cabinet..

If you have a large room..then I would suggest you look at a smaller version of these..

A single 12" or 15" bass speaker in a folded horn design with open faced horns for mid and highs will provide excellent sound for a large room..

The only downside of this is that such a design commercially built will cost a lot of money !! One or two thousand dollars for one speaker !!!

The upside is that if you're a handy person..you can build these type of speakers for a lot less..

There are kit plans available on the web..All you have to do is build the cabinets..

[EricL]

Hi @Prof

What about using stereo speakers from say 2015? The ones I'm using have two mid-range base speakers and three tweeters in a timber cabinet. I've hooked it up to an old Yamaha HTR 6030. It sounds ok but my neighbours might not appreciate the heavy base If I were to hook up the dedicated subwoofer. 

Eric

[Prof]

Hi Eric,

Generally speakers that are designed for music reproduction don't give the impact you need for movies..

If your mid /bass speakers are 10" to 12" then they might be OK..

If you buy or build speakers with strong deep bass reproduction..you can get away without using a subwoofer if you think that's going to be a problem for your neighbours..

However..deep bass has a very long sound wave and I know of situations where the immediate neighbours barely hear any bass, but a neighbour two doors away hears it very loudly..!!! You just never know what effect it has so I wouldn't rule out a subwoofer entirely..

[Noyade]

Hi @Prof. 

"Generally speakers that are designed for music reproduction don't give the impact you need for movies.."

Well, that is interesting. So what about those 'soundbars' everybody are buying these days - different again?

[Prof]

There is a problem with sound bars..They sound reasonably good for listening to TV sound..but the TV doesn't have a 100W. / ch. or so amplifier in it as you would have in a dedicated theatre.. Consequently you wouldn't get the same powerful deep sound..

The other thing is TV sound is compressed ( meaning all the peaks and dip have been flattened ) so the overall sound level remains the same for the whole frequency spectrum..

This means that the soundbar doesn't need to provide dynamic sound and this is how they get away with using small speakers..